Light-weight composites are commonly used in manufacturing cars with lighter weight and improved fuel economy. The composites are currently produced using expensive steel tools and technologically advanced compression molding machines.
Open tool molding is a process for producing relatively low cost composite panels at low volumes. While steel molds are often used for other molding operations, the open tool molding process was developed to use less expensive one-sided epoxy or polyester molds to produce various products, such as composite panels with an in-mold finish.
Alternative methods of producing light weight composites can be utilized. Open tool molding is an example of such a method. To obtain a reasonable surface appearance, the process requires the use of a gel coat followed by a supporting composite laminate. In the process, a mold surface is first cleaned, a mold release coating is optionally applied, and a layer of a gel coat is applied and partially cured. A laminate is then applied to the gel coat layer, and the laminate and gel coat are cured to form a unitary part having a surface defined by the cured gel coat. Molded parts can be produced by this method to have a finish bearing any desired color originally carried by the gel coat.
In some applications, in order to obtain a smooth surface finish on the gel coat and reduce the extent of fiber read through, a barrier coat may be applied between the gel coat and the laminate. It would be desirable to produce low density, low shrink laminate for use in such processes.